The electromagnet stroke in a disk brake generally is small, in the order of 0.7 to 1.0 mm. Therefore, when the brake lining or the like wears, increasing the electromagnet stroke, shocks and vibration will increase during braking, in addition to which unless adjustment is carried out the electromagnetic induction may become inoperative and slipping arise between the disk and the lining, causing the lining to wear rapidly and generating heat in the disk, which can result in a major accident.
Devices have been proposed, e. g., by Japanese Patent Publication No. 59(1984)-16130, for automatically correcting for an increase in the gap between the disk and the brake lining so that the gap is always maintained within the specified range. This type of device comprises a lever that is used to magnify the small movement of the armature of the electromagnet that operates the brake lining to thereby move, by one tooth at a time, a ratchet wheel that is integral with an adjusting screw for adjusting the brake lining gap.
Because a conventional device of this type employs a system of magnifying the amount of wear by means of a lever, it is necessary to use many pins and lever holes. Therefore, wear produced in the pins and lever holes gives rise to accumulated error, as a result of which a long working life with high reliability cannot hope to be achieved.
From a consideration of the aforementioned problems, an objective of the present invention is to achieve a long working life with high reliability.